1. Field
The present disclosure herein relates to organic electroluminescence display devices, and more particularly, to organic electroluminescence display devices which may achieve excellent efficiency while reducing material costs.
2. Description of the Related Art
Flat display devices may be broadly classified as emissive types and non-emissive types. The emissive types may include a flat cathode ray tube display, a plasma display panel, and an organic electroluminescence display device.
The organic electroluminescence display device is a self-emissive display, in which it may have wide viewing angles, excellent contrast, and high response speed. Accordingly, the organic electroluminescence display device is on the spot light because it may be used in displays for a mobile device, e.g., digital cameras, video cameras, camcorders, portable information terminals, smart phones, ultra-slim notebooks, tablet personal computers, and flexible displays, or in large electronic products or large electrical products, e.g., ultra-thin televisions.
The organic electroluminescence display device may generate light using a principle, in which holes and electrons respectively injected from a first electrode and a second electrode are recombined in an emission layer to emit light, wherein light is emitted when excitons formed by the recombination of the injected electrons and holes drop from an excited state to a ground state. The organic electroluminescence display device has been developed in various structures, and, among them, a tandem-type structure has emerged in which each layer between the first electrode and the second electrode is deposited without a mask.